Safety and stopping arrangement for intermittently-operating apparatus



March 31, 1931.

C. MIEDBRODT SAFETY AND STOPPING ARRANGEMENT FOR INTERMITTENTLYOPERATING APPARATUS Filed Sept. 11, 1929 I I I Patented Mar. 31, 1931UNITED STATES PATENT OFFICE SAFETY AND STOPPING ARRANGEMENT FORINTERMITTENTLY-OPEATING APPARATUS Application filed September 11, 1929,Serial No. 391,947, and in Germany March 31, 1928.

In the case of intermittently operating ap-' paratus (such as gasproducers) their closure members (such as slides, valves, clack valvesand cocks) to be controlled are frequently opened and closed by liftingcylinders operated by a pressure medium (such as water, oil, air orsteam). The lifting cylinders served by the control members are actuatedfrom a centre, the control being either auto- 1 matic by suitabledriving means (such as an electromotor) through a control shaft set inrotation thereby, or also by hand.

In intermittent apparatus of this kind, the

several closure members must be actuated in a definite serial order andat definite inter vals, and it is also necessary that each liftingcylinder, when connected up by means of the control member, shouldperform its function in an orderly manner, that is to say, at the propertime and for the prescribed eriod. p In the known arrangements employed,for example, in the case of gas producers, failure of the closuremembers to maintain orderly movement can give rise to great danger, forexample through explosions. Care must therefore be taken that not onlycan any failure in the working mechanism of the control members berendered apparent, but also that the entire apparatus can be brought toa standstill at once.

In the case of automatically controlled intermittenly operatingapparatus, the present invention provides that, in the event of theseveral closure members failing to operate in an orderly manner, theactuation of the several control members, and also of the entireapparatus, is interrupted at once. In addition, the attention of theattendant is drawn to the fact that the apparatus is out of order, bymeans of an optical and acoustic signal.

The fundamental idea of the invention consists in that, in the event ofirregular action on the part of one of the lifting cylin dens servingthe closure members, the resulting omission to complete the excitationcircult of a time switch provided for such lifting cylinder causes thebreaking of the circuit of the electromotor actuating the controlmember, after the interval for which the time switch is set has elapsed.-The arrangement is also such that, on said circuit becoming dead, arelease device therein reverses the direction of the pressure medium insuch a Way that the pressure medium (whether oil, air or the like)exerts on all the control mem bers a pressure adapted to put the closuredevices of the apparatus out of operation. The result is that, inaddition to drawing attention to the fact that the one cylinder is notoperating in an orderly manner, the entire apparatus is automaticallybrought to a standstill. The energizing action of the time switch ceasesduring the period in which the control member and the piston in thelifting cylinder perform their movements during the interval prescribedfor this opera tion. If, however, the interval prescribed for theoperation is exceeded, the circuit of the electromotor is broken inconsequence of the unduly prolonged inaction of the energizing action ofthe time switch. At the same time provision is made whereby the movementof the lever interrupting the current completes another circuitcontaining a signal lamp for each time switch, which lamp is thenlighted. Consequently, the attendant can see at once which of theclosure members has failed. In order, however, to guard against failureon the part of the attendant to notice the optical signal, there is alsoincluded in the same circuit an acoustic signal, which always soundswhen any of the signal lamps lights.

A typical embodiment of the invention is illustrated diagrammatically onthe accompanying drawing to which reference will now be made.

The closure members 1, disposed for example on a gas producer, areactuated by pistons 4 working in lifting cylinders 2 under the action ofa pressure medium 3. The serial order of operation and timing of thesepistons are controlled by their allotted control members 5, to whichmotion is imparted by cams 7, driven by an electromotor 6 and actingthrough crank levers 8. In the circuit 9 of the electromotor, a numberof interruptor levers 10, (equal to the number of lifting cylinders) aredisposed in series. According to the invention and for assuring thesafety of the apparatus, each interruptor lever is provided with a timeswitch 11 so adjusted as not to come into operation until after the timehas elapsed at which the operation initiated by the lifting cylinder isto be performed,'that is to say, either when the lifting cylinder hasnot performed its operation at all, or else has not completed it. Thecircuit including the exciting coil of the time switch 11, and limitswitches or contacts 12, 13 provided on the corresponding control memberand on the rod of the coacting piston 4, constitute an auxiliary circuitin parallel with the main or motor circuit 9, and the arrangement issuch that during the normal operation, each time the movement of thepiston (and with it the coacting control member) is reversed, thesaidauxiliary circuit is completed through the contacts 12, 13, theresult being that the release 14 of the time switch cannot exert anyaction on the corresponding interruptor lever 10 of the circuit 9. If(as shown in the case of the lifting cylinder on the right in thedrawing) a piston 4: stops through any cause and the time prescribed forthe release of the corresponding time switch 11 expires, then itsrelease 14 acts by pressing down the appropriate interruptor lever 10,thereby breaking the circuit 9 and bringing the electromotor and the cam7 to a standstill. In order, in such. case, 'to prevent any furtheraction of the operations initiated by the other lifting cylinders,provision is made for reversing the direction of flow of the pressuremedium by means of a device 15, which is released when the supply ofcurrent to the electromotor ceases and operates a two-way cock 16, sothat the pressure medium 3 then exerts on all the control members 5 apressure which sets all the closure members 1, in a positioncorresponding to the stoppage of the whole apparatus 11 order that theattention of the operative may be directed to the stoppage which hasoccurred, it is arranged that, simultaneously with the breaking of thecircuit 9 by any of the interruptor levers 10, another clrcuit 17 iscompleted in which there is provided, for each tlme switch, a signallamp 18 which thereupon lights. There is also provided in the samecircuit an acoustic signal 19 which sounds every time any of the signallamps 18 in the circuit is lighted.

It will be understood that the described safety device can also besuitably applied to controls in which the control members 5 are manuallyoperated. In such case the stoppage of the electromotor and thereversing of the pressure medium by the time switch is dispensed with.

I claim 1. A safety stopping arrangement for intermittently operatingapparatus, comprising in combination, at least one fluid actuated pistonfor actuating the operating parts of said apparatus, at least one pistonvalve for controlling the flow of the fluid to said pistons, at leastone rotary cam device for actuating said control valves to stop saidpistons, an electric motor for driving said rotary cam device, a timeswitch adapted to cut out said electric motor and therefore the drive onsaid cam device controls when the operation of any of the intermittentlyoperating parts ceases, and a secondary control device adapted to beoperated when said electric motor is cut out, to actuate said pistonvalves to stop the whole apparatus.

2. A safety stopping arrangement for intermittently reciprocative,apparatus, comprising in combination, fluid actuated pistons forreciprocating said apparatus, fluid actuated piston valves forcontrolling the flow of the fluid to said pistons, rotary cam devicesfor controlling the operation of said piston valves, at least oneelectric motor for driving said rotary cam devices and electric timeswitches adapted, on the operation of the intermittently reciprocativeapparatus becoming abnormal, to bring into operation means which cut outsaid electric motor, give a warning signal and control the supply offluid to the piston valves, causing them to take positions which causethe operation of the fluid actuated pistons and therefore of thereciprocative apparatus to cease.

3. A safety stopping arrangement for intermittently reciprocativeapparatus, comprising in combination, fluid actuated pistons forreciprocating said apparatus, fluid actuated piston valves forcontrolling the flow of the fluid to said pistons, rotary cam devicesfor controlling the operation of said piston valves, at least oneelectric motor for driving said rotary cam devices, pairs of contactsone of each pair carried by one of said fluid actuated pistons and theother of each pair carried by one of said piston valves, each of saidpairs, of contacts being adapted to coact together normally to keep theelectric circuit of said electric motor closed, but also adapted, whenthe operation of any of the intermittently reciprocative parts ecomesabnormal to open the circuit of said electric motor to give audible andvisual signals and to stop the operation of the intermittentlyreciprocative apparatus.

4. A safety stopping arrangement for intermittently reciprocativeapparatus, comprising in combination, fluid actuated istons forreciprocating said apparatus, uid actuated piston valves for controllingthe flow of the fluid to said pistons, rotary cam devices forcontrolling the operation of said piston valves, at least one electricmotor for driving said rotary cam devices, pairs of contacts one of eachpair carried by one of said fluid actuated pistons and the other of eachpair carried by one of said iston valves each of said pairs of contactseing adapted to coact together normally to keep the electric circuit ofsaid electric motor closed, but also adapted, when the operation of anyof the intermittently reciprocative arts -becomes abnormal to open thecircuit of said electric motor, simultaneously com leting anothercircuit containing for eacfl time switch, a signal lamp which thereuponlights up, and the opening of said motor circuit also actuating atwo-way valve which caused the fluid to actuate the said piston valvesand to stop the operation of the intermittently reciprocative apparatus.

5. A safety stopping arrangement for intermittently .reciprocativeapparatus, comprising in combination, fluid actuated pistons forreciprocating said apparatus, fluid actuated piston valves forcontrolling the flow of the fluid to said pistons, rotary cam devicesfor controlling the operation of said piston valves, at least oneelectric motor for driving said rotary cam devices, pairs of contactsone of each pair carried by one of said fluid actuated pistons and theother of each pair carried by one of said piston valves, each of saidpairs of contacts being adapted to coact together normally to keep theelectric circuit of said electric motor closed, but also adapted, whenthe operation of any of the intermittently reciprocative parts becomesabnormal to open the circuit of said electric motor, simultaneouslycompleting another circuit containing for each time switch, a signallamp which thereupon lights up, and an acoustic signal which thereuponsounds, and the opening of said motor circuit also actuating a two-wayvalve which causes the fluid to actuate the said piston valves and tostop the operation of the intermittently reoiprocative apparatus.

In testimony whereof I aflix my signature.

CARL MI'EDBRO-DT.

